Columbus, OH Pollen Levels Today

Columbus, Ohio sits in a humid continental climate zone within the Scioto River valley, creating a long and often intense allergy calendar that spans roughly February through October.

The season typically opens with tree pollen in late winter and early spring, when cedar, elm, and maple release first, followed by oak, birch, sycamore, hickory, ash, and walnut through April and May—oak being one of the most prolific local offenders.

As tree counts taper, grass pollen takes over from mid-May into July, driven largely by Kentucky bluegrass, timothy, orchard grass, and fescue, all common across central Ohio lawns and farmland. This late-spring handoff creates a notable overlap period in May and June when trees and grasses circulate simultaneously, often intensifying symptoms.

Weed season dominates late summer into fall, with ragweed as the principal culprit from mid-August through the first hard frost in October, joined by pigweed, lamb's quarters, and plantain.

Beyond pollen, Columbus's humidity fuels persistent outdoor and indoor mold (especially Alternaria and Cladosporium), while urban air quality, ozone, and agricultural dust from surrounding farmland add year-round irritants.

Overall, Columbus presents a long, overlapping, high-pollen profile shaped by diverse hardwoods, humid summers, and heavy ragweed exposure.